Question 1. Sa Pa / known / its / beautiful / mountains / valleys.

Sapa is known for its beautiful mountains and valleys

Question 2. British children / hang / small bells / gifts / Christmas trees.

British children hang small bells and gifts on Christmas trees

Question 3. If / you / not / take off / shoes, you / make / carpet / dirty.

If you don't take off your shoes, you will make the carpet dirty

Question 4. Our school / have / tradition / hold / talent show / every spring.

Our school have the tradition of holding a talent show every spring

Question 5. Vietnamese students / visit / Temple of Literature / pray / good luck.

Vietnamese students visit the Temple of Literature to pray for good luck

Question 1:Sapa is known for its beautiful mountains and valleys                                                                                                              Question 2:British children hang small bells and gifts on Christmas trees                                                                                                    Question 3:If you don't take off your shoes, you will make the carpet dirty                                                                                                    Questioon 4:Our school have the tradition of holding a talent show every spring                                                                                         Question 5:Vietnamese students visit the Temple of Literature to pray for good luck

is the smallest room.

............ is smallest room in the house.

\(3x\left(x+1\right)-2x\left(x+1\right)=-x-1\)

\(\Leftrightarrow\left(x+1\right)\left(3x-2x\right)=-\left(x+1\right)\)

\(\Leftrightarrow\left(x+1\right)x+\left(x+1\right)=0\)

\(\Leftrightarrow\left(x+1\right)^2=0\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)

Ta có: \(n_{H_2}=\dfrac{2,479}{24,79}=0,1\left(mol\right)\)

Theo ĐLBT KL: m_Zn + m_H2SO4 = m_ZnSO4 + m_H2

⇒ m_H2SO4 = 9 + 0,1.2 - 6,5 = 2,7 (g)

Ex1

1 prevent

2 environment

3 recycle

4 affects

5 harm

6 caused

7 issue

8 health

9 burned

10 coughed

11 damade

12 lung

13 disease

14 pollution

15 heart

Ex2

1 polluted

2 healthily

3 Prevention

4 environmentally

5 reduction

6 saving

7 harmlessly

8 electrician

9 poisonous 

10 protection

11 wasteful

12 tourism

13 organized

14 removement

15 cleaner

\(\left(2x+3\right)^2-4x^2=10\\ \Leftrightarrow\left(4x^2+12x+9\right)-4x^2=10\\ \Leftrightarrow4x^2-4x^2+12x=10-9\\ \Leftrightarrow12x=1\\ \Leftrightarrow x=\dfrac{1}{12}\)

\(\left(x+1\right)^2-3\left(x+1\right)=\left(x+1\right)\left(x+1-3\right)=\left(x+1\right)\left(x-2\right)\)

\(2x\left(x-2\right)-\left(x-2\right)^2=\left(x-2\right)\left[2x-\left(x-2\right)\right]=\left(x-2\right)\left(2x-x+2\right)=\left(x-2\right)\left(x+2\right)\)

\(4x^2-20xy+25y^2=\left(2x\right)^2-2.2x.5y+\left(5y\right)^2=\left(2x-5y\right)^2\)

\(x^2+3x-x-3=x\left(x+3\right)-\left(x+3\right)=\left(x-1\right)\left(x+3\right)\)

\(x^2-xy+x-y=x\left(x-y\right)+\left(x-y\right)=\left(x-y\right)\left(x+1\right)\)

\(2y\left(x+2\right)-3x-6=2y\left(x+2\right)-3\left(x+2\right)=\left(x+2\right)\left(2y-3\right)\)

`a, 8xy^2-2x^2y`

`= 2xy ( 4y - x)`

`b, x(x-y) -y(y-x)`

`= x(x-y) + y(x-y)`

`= (x-y)(x+y)`

`c, x(x-1) + (1-x)^2`

`= x(x-1)+(x-1)^2`

`= (x-1) (x+x-1)`

`=(x-1)(2x-1)`